Solution: extract common code into functions

Solution: return NULL and set errno to ENOMEM

Problem: inconsistent behaviour of zmq_poller_add and zmq_poller_add_fd in case of memory exhaustion

Solution: always return -1 with errno == ENOMEM

Solution: if a PING message contains a context, echo it back in the
PONG message. In order to do so, create the PONG message when PING
is received and store it in the engine.
After the PING the engine goes straight to encoding and sending, so
there can always be at most one pending PING.
Add tests for various contexts.

Solution: treat the first byte of the command body as the size of the
command name, rather than as an id, to comply with ZMTP 3.1.
This was not an actual problem at runtime since both heartbeat
commands have a size of 4, which was treated like an id.
But once SUBSCRIBE/UNSUBSCRIBE get implemented it needs to be checked.

Solution: initialise it

Solution: add compiler flags to support extensions like anonymous
structs in unions, fix casting of const, and check for suncc rather
than solaris

Solution: if a binding interface is provided in the sender URL we pass
it to IP[V6]_MULTICAST_IF setsockopt

Solution: add missing const qualifier to internal functions

Solution: do it explicitly to fix build on Solaris 10/11 with the Sun
compiler

Solution: remove constness on pair arguments. Fixes #3090

Solution: use proper types

Solution: add a new ZMQ_MULTICAST_LOOP option for UDP sockets.

Solution: Add IPv6 support

for multicast

Solution: augment the UDP URL syntax to accept an interface specifier with a
syntax similar to the PGM urls.

Fixes #2212

Solution: factor the code into ip_resolver, add IPv6 support and unit tests.

Solution: replace it with the ip_resolver code shared with the TCP
address code

It simplifies the UDP parsing code and makes it behave more like the
TCP counterpart, in particular it's not possible to connect to hosts
by name and bind by NIC names.

It also adds support for "*" port resolving to 0 (useful to let the OS
allocate the port number).

Solution: return an error in this situation but still allow using an explicit
"0" if somebody really wants to connect to port 0.

This shouldn't break any existing code because a "*" port was already rejected
in an early test in the TCP path in zmq::socket_base_t::connect.

Solution: Factor the code into a different file with a well defined API and add
unit tests.

Solution: ignore command messages in the REQ session to avoid
disrupting the state machine.
Commands are handled by the engine before handing off to the session.

event_accepted() already accepts fd_t type and there is no reason to cast it to int type
Moreover, on Windows x64 this leads to truncation memsize -> int

* Implement the wsa_error_no function with switch-case
Signed-off-by: Asaf Kahlon <asafka7@gmail.com>

Solution: change missing comments in header file
Fixes: #3036 and adds on top of '15905c55'

Solution: change comments
Fixes: #3036

Solution: do not call getsockopt to query thread-safety of a socket

Solution: revert the revert!

Revert "Problem: regression in 4.2.3 went unnoticed, want to release 4.2.5"

This reverts commit 5f17e26f.

Solution: revert DRAFT -> STABLE API transition so that we can do a
bugfix-only 4.2.5 release.
Will be re-reverted once tagged.

Revert "Problem: ZMQ_BINDTODEVICE has met STABLE conditions"

This reverts commit 3cb79f50.

Revert "Problem: ZMQ_MSG_GSSAPI_* have met STABLE conditions"

This reverts commit 374da420.

Revert "Problem: ZMQ_MSG_T_SIZE has met STABLE conditions"

This reverts commit 6411c4a2.

Revert "Problem: docs say STABLE API still in DRAFT"

This reverts commit 9f2f30b7.

Solution: like for other mechanism, do not enforce strict ZAP protocol
adherence unless the specific socket option is enabled with NULL auth.

Add test to exercise this functionality, and fix ZAP test to set the
socket option when it uses NULL auth.

See: https://github.com/zeromq/pyzmq/pull/1152

Solution: move them from DRAFT to STABLE since it's been in a public
release, committed for 6+ months and has not changed.

Solution: move them from DRAFT to STABLE since it's been in a public
release, committed for 6+ months and has not changed.

Solution: move it from DRAFT to STABLE since it's been in a public
release, committed for 6+ months and has not changed.
Given a new STABLE symbol has been added, bump minor version number.

Solution: restrict it only to the original issue #2632, Tweetnacl on
*NIX when using /dev/urandom, ie: without the new Linux getrandom()
syscall.

Existing applications might use atexit to register cleanup functions
(like CZMQ does), and the current change as-is imposes an ordering
that did not exist before - the context MUST be created BEFORE
registering the cleanup with atexit. This is a backward incompatible
change that is reported to cause aborts in some applications.

Although libsodium's documentation says that its initialisation APIs
is not thread-safe, nobody has ever reported an issue with it, so
avoiding the global init/deinit in the libsodium case is the less
risky option we have.

Tweetnacl users on Windows and on Linux with getrandom (glibc 2.25 and
Linux kernel 3.17) are not affected by the original issue.

Fixes #2991

Lets the application set per-connection metadata.
Metadata is specified as "X-key:value" and set using zmq_setsockopt, eg:
zmq_setsockopt (s, ZMQ_METADATA, "X-key:value", 11);

The peer can then obtain the metadata from a received message:
char *data = zmq_msg_gets(msg, "X-key");

* Fixes issue 2963, ref stream_engine.cpp:981

* Fixes issue 2963, ref socks_connecter.cpp:158

* Fixes issue 2963, ref tcp_listener.cpp:144

* Fixes issue 2963, ref tcp_connecter.cpp:423

* Fixes issue 2963, ref socks_connecter.cpp:436

* Fixes issue 2963, ref tcp_listener.cpp:179

* Fixes issue 2963, ref tcp_listener.cpp:268

* Fixes issue 2963, ref tcp_connecter.cpp:160

Solution: commit clang-format-diff

Solution: add pragma to make clang-format ignore the external code

* Problem: Still need to port over more files to VxWorks 6.x

Solution: Port more files to VxWorks 6.x

* Problem: Need to port over remaining files to VxWorks 6.x. Also remove POSIX thread dependency for VxWorks (because of priority inversion problem in POSIX mutexes with VxWorks 6.x processes)

Solution: Port over remaining files to VxWorks 6.x. Also removed POSIX thread dependency for VxWorks

* Problem: Needed to modify TCP, UDP, TIPC classes with #ifdefs to be compatible with VxWorks 6.x.

Solution:  Modify TCP, UDP, TIPC classes with #ifdefs to be compatible with VxWorks 6.x